1. Field of the Invention
The present invention relates to an X-ray diagnostic apparatus of a circulatory organ system to be used to inspect the circulatory organ system.
2. Description of the Related Art
An X-ray diagnostic apparatus of a circulatory organ system is an apparatus for X-ray inspecting a heat, a coronary artery, an abdominal blood vessel, or a blood vessel of lower limbs so as to catch the circulation of blood, running of blood vessel, form of blood vessel, and movement of the valves by injecting a radiopaque substance into the blood vessel and following the flow of image-forming agent. As compared with the other X-ray diagnostic apparatus of a digestive organ system, the technique of much shorter time X-ray irradiation and much higher speed image-forming are required since the object, which the diagnostic apparatus of a circulatory organ system inspects, is the circulation of blood, which moves, the fastest in the human body.
Moreover, the blood vessel, particularly, the blood vessel of the heart or the blood vessel of the encephalon, complicatedly runs around the heart or the encephalon, making, it difficult to observe the running state by an image, which is imaged-formed in one direction. Therefore, it is required that the image-forming be made in the multi-direction. There has been developed the so-called simultaneous, two directional image-forming apparatus wherein a supporting mechanism of image-forming system, having a good operating ability, such that the multi-directional image-forming can be performed, and a simultaneous image-forming is performed in the two directions. Moreover, the technique of the stereoscopic vision, which can observe the complicated running state of the blood vessel as it is, has been developed and practically used.
FIG. 19 is a view explaining the principle of the stereoscopic vision (stereophotographing).
An X-ray tube 90 has a focal point 91R for a right eye and a focal point 91L for a left eye, which are arranged to be spaced from each other in accordance with a distance (parallax) between right and left eyes of the human being. An observer can obtain perspective when he observes two films 92 image-formed at two focal points 91R and 91L with his right and left eyes.
FIG. 20 is a side view of a conventional ceiling suspension type simultaneous two directional image-forming apparatus. This simultaneous two directional image-forming apparatus has its image-forming system supported by a ceiling base 102 movably supported to two rails 101 provided on the lower surface of the ceiling in its back and front direction, an arm base 103 rotatably supported by the ceiling base 102, a suspension arm 104 expandable in a direction that the arm is supported, a support block 105 attached to the suspension arm 104, a ring base 106 rotatably supported by the support block 105 in a direction of an arrow A, and a C-shaped ring 107 supported by the ring base 106 to be slidable in a direction of an arrow B.
In the C-shaped ring 107, two image-forming systems are arranged to be orthogonal to each other at a central point Q of the C-shaped ring 107. The image system, which is arranged to be opposed to a ceiling plate, is hereinafter called "front system" and other image-forming system is hereinafter called "side system."
Both image-forming systems have the same structural elements. That is, both image-forming systems comprise X-ray apparatuses 110 and 111 having an X-ray tube for radiating an X ray and an aperture-setting apparatus for restricting an X-ray radiation field, image systems 112 and 113 having an image intensifier (I.I), which is arranged to be opposed to the X-ray apparatus 110, 111 to sandwich the central point Q therebetween, an optical system, and a TV camera, and a film changer (not shown) for holding an X-ray film.
First, an operator operates the image systems 112 and 113 and changes the operation to the operation of the film changer at a predetermined time as seeing through a patient. Thereafter, the operator image-forms a predetermined image in the film.
The above-structured simultaneous two-directional image-forming apparatus can simultaneously image-form the patient P in two direction orthogonal to each other in the form of dorsal decubits without moving the patient P.
However, as shown in FIG. 21, the ring base 106 is rotated in the direction of arrow A to the support block 105 in order to carry out the so-called inclination image-forming, that is, the image-forming is carried out at an inclination of an angle other than 90.degree. to an body axis PL of the patient by use of the front system. As a result, the side system is rotated in accordance with the rotation of the ring base 106, and the image displayed on a monitor is rotated, and such an image is difficult to observe.
The same point can be said in the case that the film changer is operated at a predetermined time and the X-ray image is formed in the film. That is, the film changer is rotated in accordance with the rotation of the ring base 106, and the X-ray image is formed in the film in the inclination form.
The image-forming has been conventionally performed in a state that the patient is standing erect or lying horizontally, and the diagnosis can be easily performed in such a state in view of sensibility. Conventionally, the film was inclined and attached to the sheet film viewer such that the image formed in the film in the inclination form is changed to the above erect state, and this was extremely inconvenient.
In order to solve the above problem, as shown in FIG. 22, there was developed an apparatus in which only the side system is held on the C-shaped ring 107, and an auxiliary arm 120 for holding the front system is provided separately from the C-shaped ring 107, and so that the front system and the side system can be separately rotated. According to this apparatus, only the auxiliary arm 120 may be rotated when the inclination image-forming is performed, and the original horizontal state of the side system can be maintained.
However, by the provision of the auxiliary arm 120, the structure of the apparatus extremely became complicated, and the apparatus had to be large-sized.
The problems of the stereophotographing will be explained.
FIG. 23 is a side view of a conventional multi-directional image-forming apparatus wherein one image-forming system is provided and the stereophotographing can be performed. FIG. 24 is a front view of FIG. 23, and FIG. 25 is a perspective view showing a focal point of an X-ray tube. The same portions reference numerals are added to the same portions as the portions of FIG. 20, and the explanation is omitted.
As shown in FIG. 25, an X-ray tube 108 has two focal points 108L for a left eye and 108R for a right eye, which are spaced from each other based on the parallax between right and left eyes of the human being, in the surface of a rotation anode 115. The observer can obtain a stereoscopic feeling by seeing two images, which are formed at two focal points 108L and 108R, with his right and left eyes.
However, in a case where the observer wishes to obtain the stereoscopic vision of the erect state, the insertion direction of the patient to the image-forming region is restricted. The reason will be explained as follows:
The case in which the head of the patient P is inserted from the front of the apparatus of FIG. 23 is hereinafter called "front insertion" and the case in which the head of the patient P is inserted from the side of the apparatus of FIG. 24 is hereinafter called "side insertion."
In the case of "front insertion", the X-ray tube 108 and the TV camera 25 are set so as to obtain the erect state of the image of the patient. For example, as shown in FIG. 26, the X-ray tube 108 is mounted on the C-shaped ring 107 such that the focal point 108L is positioned at the right side of the patient P to which the front insertion is provided and the focal point 108R is positioned at the left side thereof. Due to this, in the case of "side insertion", as shown in FIG. 27, two focal points 108L and 108R for the left and right eyes of the X-ray tube are arranged along the body axis PL of the patient P. In a case where the observer performs the stereoscopic vision by the two images obtained in the above state of the arrangement, the stereoscopic vision in which the patient P is lying. For the stereoscopic vision, it is needed that two images are arranged in accordance with the positional relation between two images at the time of image-forming and observed. Due to this, for example, even if the observer views two images for right and left eyes in a state that these two images are rotated at 90.degree., the observer cannot obtain the desirable stereoscopic vision between the images. As mentioned above, in obtaining the stereoscopic vision of the image of the upright patient, the insertion direction of the patient P to the image-forming region was readily determined by the attaching state of the x-ray tube 108 to the C-shaped ring 107, which was extremely inconvenient.